postinit.c

/*------------------------------------------------------------------------- * * postinit.c * postgres initialization utilities * * Portions Copyright (c) 1996-2009, PostgreSQL Global Development Group * Portions Copyright (c) 1994, Regents of the University of California * * * IDENTIFICATION * $PostgreSQL: pgsql/src/backend/utils/init/postinit.c,v 1.191.2.1 2009/07/08 17:53:32 heikki Exp $ * * *------------------------------------------------------------------------- */#include "postgres.h"#include <fcntl.h>#include <unistd.h>#include "access/heapam.h"#include "access/xact.h"#include "catalog/catalog.h"#include "catalog/namespace.h"#include "catalog/pg_authid.h"#include "catalog/pg_database.h"#include "catalog/pg_tablespace.h"#include "libpq/hba.h"#include "libpq/libpq-be.h"#include "mb/pg_wchar.h"#include "miscadmin.h"#include "pgstat.h"#include "postmaster/autovacuum.h"#include "postmaster/postmaster.h"#include "storage/backendid.h"#include "storage/bufmgr.h"#include "storage/fd.h"#include "storage/ipc.h"#include "storage/lmgr.h"#include "storage/proc.h"#include "storage/procarray.h"#include "storage/sinvaladt.h"#include "storage/smgr.h"#include "utils/acl.h"#include "utils/flatfiles.h"#include "utils/guc.h"#include "utils/pg_locale.h"#include "utils/plancache.h"#include "utils/portal.h"#include "utils/relcache.h"#include "utils/snapmgr.h"#include "utils/syscache.h"#include "utils/tqual.h"staticbool FindMyDatabase(constchar *name, Oid *db_id, Oid *db_tablespace);
staticbool FindMyDatabaseByOid(Oid dbid, char *dbname, Oid *db_tablespace);
staticvoid CheckMyDatabase(constchar *name, bool am_superuser);
staticvoid InitCommunication(void);
staticvoid ShutdownPostgres(int code, Datum arg);
staticbool ThereIsAtLeastOneRole(void);
/*** InitPostgres support ***//* * FindMyDatabase -- get the critical info needed to locate my database * * Find the named database in pg_database, return its database OID and the * OID of its default tablespace. Return TRUE if found, FALSE if not. * * Since we are not yet up and running as a backend, we cannot look directly * at pg_database (we can't obtain locks nor participate in transactions). * So to get the info we need before starting up, we must look at the "flat * file" copy of pg_database that is helpfully maintained by flatfiles.c. * This is subject to various race conditions, so after we have the * transaction infrastructure started, we have to recheck the information; * see InitPostgres. */staticbool
FindMyDatabase(constchar *name, Oid *db_id, Oid *db_tablespace)
{
bool result = false;
char *filename;
FILE *db_file;
char thisname[NAMEDATALEN];
TransactionId db_frozenxid;
filename = database_getflatfilename();
db_file = AllocateFile(filename, "r");
if (db_file == NULL)
ereport(FATAL,
(errcode_for_file_access(),
errmsg("could not open file \"%s\": %m", filename)));
while (read_pg_database_line(db_file, thisname, db_id,
db_tablespace, &db_frozenxid))
{
if (strcmp(thisname, name) == 0)
{
result = true;
break;
}
}
FreeFile(db_file);
pfree(filename);
return result;
}
/* * FindMyDatabaseByOid * * As above, but the actual database Id is known. Return its name and the * tablespace OID. Return TRUE if found, FALSE if not. The same restrictions * as FindMyDatabase apply. */staticbool
FindMyDatabaseByOid(Oid dbid, char *dbname, Oid *db_tablespace)
{
bool result = false;
char *filename;
FILE *db_file;
Oid db_id;
char thisname[NAMEDATALEN];
TransactionId db_frozenxid;
filename = database_getflatfilename();
db_file = AllocateFile(filename, "r");
if (db_file == NULL)
ereport(FATAL,
(errcode_for_file_access(),
errmsg("could not open file \"%s\": %m", filename)));
while (read_pg_database_line(db_file, thisname, &db_id,
db_tablespace, &db_frozenxid))
{
if (dbid == db_id)
{
result = true;
strlcpy(dbname, thisname, NAMEDATALEN);
break;
}
}
FreeFile(db_file);
pfree(filename);
return result;
}
/* * CheckMyDatabase -- fetch information from the pg_database entry for our DB */staticvoid
CheckMyDatabase(constchar *name, bool am_superuser)
{
HeapTuple tup;
Form_pg_database dbform;
char *collate;
char *ctype;
/* Fetch our real pg_database row */
tup = SearchSysCache(DATABASEOID,
ObjectIdGetDatum(MyDatabaseId),
0, 0, 0);
if (!HeapTupleIsValid(tup))
elog(ERROR, "cache lookup failed for database %u", MyDatabaseId);
dbform = (Form_pg_database) GETSTRUCT(tup);
/* This recheck is strictly paranoia */if (strcmp(name, NameStr(dbform->datname)) != 0)
ereport(FATAL,
(errcode(ERRCODE_UNDEFINED_DATABASE),
errmsg("database \"%s\" has disappeared from pg_database",
name),
errdetail("Database OID %u now seems to belong to \"%s\".",
MyDatabaseId, NameStr(dbform->datname))));
/* * Check permissions to connect to the database. * * These checks are not enforced when in standalone mode, so that there is * a way to recover from disabling all access to all databases, for * example "UPDATE pg_database SET datallowconn = false;". * * We do not enforce them for the autovacuum worker processes either. */if (IsUnderPostmaster && !IsAutoVacuumWorkerProcess())
{
/* * Check that the database is currently allowing connections. */if (!dbform->datallowconn)
ereport(FATAL,
(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
errmsg("database \"%s\" is not currently accepting connections",
name)));
/* * Check privilege to connect to the database. (The am_superuser test * is redundant, but since we have the flag, might as well check it * and save a few cycles.) */if (!am_superuser &&
pg_database_aclcheck(MyDatabaseId, GetUserId(),
ACL_CONNECT) != ACLCHECK_OK)
ereport(FATAL,
(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
errmsg("permission denied for database \"%s\"", name),
errdetail("User does not have CONNECT privilege.")));
/* * Check connection limit for this database. * * There is a race condition here --- we create our PGPROC before * checking for other PGPROCs. If two backends did this at about the * same time, they might both think they were over the limit, while * ideally one should succeed and one fail. Getting that to work * exactly seems more trouble than it is worth, however; instead we * just document that the connection limit is approximate. */if (dbform->datconnlimit >= 0 &&
!am_superuser &&
CountDBBackends(MyDatabaseId) > dbform->datconnlimit)
ereport(FATAL,
(errcode(ERRCODE_TOO_MANY_CONNECTIONS),
errmsg("too many connections for database \"%s\"",
name)));
}
/* * OK, we're golden. Next to-do item is to save the encoding info out of * the pg_database tuple. */
SetDatabaseEncoding(dbform->encoding);
/* Record it as a GUC internal option, too */
SetConfigOption("server_encoding", GetDatabaseEncodingName(),
PGC_INTERNAL, PGC_S_OVERRIDE);
/* If we have no other source of client_encoding, use server encoding */
SetConfigOption("client_encoding", GetDatabaseEncodingName(),
PGC_BACKEND, PGC_S_DEFAULT);
/* assign locale variables */
collate = NameStr(dbform->datcollate);
ctype = NameStr(dbform->datctype);
if (pg_perm_setlocale(LC_COLLATE, collate) == NULL)
ereport(FATAL,
(errmsg("database locale is incompatible with operating system"),
errdetail("The database was initialized with LC_COLLATE \"%s\", "" which is not recognized by setlocale().", collate),
errhint("Recreate the database with another locale or install the missing locale.")));
if (pg_perm_setlocale(LC_CTYPE, ctype) == NULL)
ereport(FATAL,
(errmsg("database locale is incompatible with operating system"),
errdetail("The database was initialized with LC_CTYPE \"%s\", "" which is not recognized by setlocale().", ctype),
errhint("Recreate the database with another locale or install the missing locale.")));
/* Make the locale settings visible as GUC variables, too */
SetConfigOption("lc_collate", collate, PGC_INTERNAL, PGC_S_OVERRIDE);
SetConfigOption("lc_ctype", ctype, PGC_INTERNAL, PGC_S_OVERRIDE);
/* Use the right encoding in translated messages */#ifdef ENABLE_NLS pg_bind_textdomain_codeset(textdomain(NULL));
#endif/* * Lastly, set up any database-specific configuration variables. */if (IsUnderPostmaster)
{
Datum datum;
bool isnull;
datum = SysCacheGetAttr(DATABASEOID, tup, Anum_pg_database_datconfig,
&isnull);
if (!isnull)
{
ArrayType *a = DatumGetArrayTypeP(datum);
/* * We process all the options at SUSET level. We assume that the * right to insert an option into pg_database was checked when it * was inserted. */
ProcessGUCArray(a, PGC_SUSET, PGC_S_DATABASE, GUC_ACTION_SET);
}
}
ReleaseSysCache(tup);
}
/* -------------------------------- * InitCommunication * * This routine initializes stuff needed for ipc, locking, etc. * it should be called something more informative. * -------------------------------- */staticvoid
InitCommunication(void)
{
/* * initialize shared memory and semaphores appropriately. */if (!IsUnderPostmaster) /* postmaster already did this */
{
/* * We're running a postgres bootstrap process or a standalone backend. * Create private "shmem" and semaphores. */
CreateSharedMemoryAndSemaphores(true, 0);
}
}
/* * Early initialization of a backend (either standalone or under postmaster). * This happens even before InitPostgres. * * If you're wondering why this is separate from InitPostgres at all: * the critical distinction is that this stuff has to happen before we can * run XLOG-related initialization, which is done before InitPostgres --- in * fact, for cases such as the background writer process, InitPostgres may * never be done at all. */void
BaseInit(void)
{
/* * Attach to shared memory and semaphores, and initialize our * input/output/debugging file descriptors. */
InitCommunication();
DebugFileOpen();
/* Do local initialization of file, storage and buffer managers */
InitFileAccess();
smgrinit();
InitBufferPoolAccess();
}
/* -------------------------------- * InitPostgres * Initialize POSTGRES. * * The database can be specified by name, using the in_dbname parameter, or by * OID, using the dboid parameter. In the latter case, the computed database * name is passed out to the caller as a palloc'ed string in out_dbname. * * In bootstrap mode no parameters are used. * * The return value indicates whether the userID is a superuser. (That * can only be tested inside a transaction, so we want to do it during * the startup transaction rather than doing a separate one in postgres.c.) * * As of PostgreSQL 8.2, we expect InitProcess() was already called, so we * already have a PGPROC struct ... but it's not filled in yet. * * Note: * Be very careful with the order of calls in the InitPostgres function. * -------------------------------- */bool
InitPostgres(constchar *in_dbname, Oid dboid, constchar *username,
char **out_dbname)
{
bool bootstrap = IsBootstrapProcessingMode();
bool autovacuum = IsAutoVacuumWorkerProcess();
bool am_superuser;
char *fullpath;
char dbname[NAMEDATALEN];
/* * Set up the global variables holding database id and path. But note we * won't actually try to touch the database just yet. * * We take a shortcut in the bootstrap case, otherwise we have to look up * the db name in pg_database. */if (bootstrap)
{
MyDatabaseId = TemplateDbOid;
MyDatabaseTableSpace = DEFAULTTABLESPACE_OID;
}
else
{
/* * Find tablespace of the database we're about to open. Since we're * not yet up and running we have to use one of the hackish * FindMyDatabase variants, which look in the flat-file copy of * pg_database. * * If the in_dbname param is NULL, lookup database by OID. */if (in_dbname == NULL)
{
if (!FindMyDatabaseByOid(dboid, dbname, &MyDatabaseTableSpace))
ereport(FATAL,
(errcode(ERRCODE_UNDEFINED_DATABASE),
errmsg("database %u does not exist", dboid)));
MyDatabaseId = dboid;
/* pass the database name to the caller */
*out_dbname = pstrdup(dbname);
}
else
{
if (!FindMyDatabase(in_dbname, &MyDatabaseId, &MyDatabaseTableSpace))
ereport(FATAL,
(errcode(ERRCODE_UNDEFINED_DATABASE),
errmsg("database \"%s\" does not exist",
in_dbname)));
/* our database name is gotten from the caller */
strlcpy(dbname, in_dbname, NAMEDATALEN);
}
}
fullpath = GetDatabasePath(MyDatabaseId, MyDatabaseTableSpace);
SetDatabasePath(fullpath);
/* * Finish filling in the PGPROC struct, and add it to the ProcArray. (We * need to know MyDatabaseId before we can do this, since it's entered * into the PGPROC struct.) * * Once I have done this, I am visible to other backends! */
InitProcessPhase2();
/* * Initialize my entry in the shared-invalidation manager's array of * per-backend data. * * Sets up MyBackendId, a unique backend identifier. */
MyBackendId = InvalidBackendId;
SharedInvalBackendInit();
if (MyBackendId > MaxBackends || MyBackendId <= 0)
elog(FATAL, "bad backend id: %d", MyBackendId);
/* * bufmgr needs another initialization call too */
InitBufferPoolBackend();
/* * Initialize local process's access to XLOG. In bootstrap case we may * skip this since StartupXLOG() was run instead. */if (!bootstrap)
InitXLOGAccess();
/* * Initialize the relation cache and the system catalog caches. Note that * no catalog access happens here; we only set up the hashtable structure. * We must do this before starting a transaction because transaction abort * would try to touch these hashtables. */
RelationCacheInitialize();
InitCatalogCache();
InitPlanCache();
/* Initialize portal manager */
EnablePortalManager();
/* Initialize stats collection --- must happen before first xact */if (!bootstrap)
pgstat_initialize();
/* * Set up process-exit callback to do pre-shutdown cleanup. This has to * be after we've initialized all the low-level modules like the buffer * manager, because during shutdown this has to run before the low-level * modules start to close down. On the other hand, we want it in place * before we begin our first transaction --- if we fail during the * initialization transaction, as is entirely possible, we need the * AbortTransaction call to clean up. */
on_shmem_exit(ShutdownPostgres, 0);
/* * Start a new transaction here before first access to db, and get a * snapshot. We don't have a use for the snapshot itself, but we're * interested in the secondary effect that it sets RecentGlobalXmin. */if (!bootstrap)
{
StartTransactionCommand();
(void) GetTransactionSnapshot();
}
/* * Now that we have a transaction, we can take locks. Take a writer's * lock on the database we are trying to connect to. If there is a * concurrently running DROP DATABASE on that database, this will block us * until it finishes (and has updated the flat file copy of pg_database). * * Note that the lock is not held long, only until the end of this startup * transaction. This is OK since we are already advertising our use of * the database in the PGPROC array; anyone trying a DROP DATABASE after * this point will see us there. * * Note: use of RowExclusiveLock here is reasonable because we envision * our session as being a concurrent writer of the database. If we had a * way of declaring a session as being guaranteed-read-only, we could use * AccessShareLock for such sessions and thereby not conflict against * CREATE DATABASE. */if (!bootstrap)
LockSharedObject(DatabaseRelationId, MyDatabaseId, 0,
RowExclusiveLock);
/* * Recheck the flat file copy of pg_database to make sure the target * database hasn't gone away. If there was a concurrent DROP DATABASE, * this ensures we will die cleanly without creating a mess. */if (!bootstrap)
{
Oid dbid2;
Oid tsid2;
if (!FindMyDatabase(dbname, &dbid2, &tsid2) ||
dbid2 != MyDatabaseId || tsid2 != MyDatabaseTableSpace)
ereport(FATAL,
(errcode(ERRCODE_UNDEFINED_DATABASE),
errmsg("database \"%s\" does not exist",
dbname),
errdetail("It seems to have just been dropped or renamed.")));
}
/* * Now we should be able to access the database directory safely. Verify * it's there and looks reasonable. */if (!bootstrap)
{
if (access(fullpath, F_OK) == -1)
{
if (errno == ENOENT)
ereport(FATAL,
(errcode(ERRCODE_UNDEFINED_DATABASE),
errmsg("database \"%s\" does not exist",
dbname),
errdetail("The database subdirectory \"%s\" is missing.",
fullpath)));
else
ereport(FATAL,
(errcode_for_file_access(),
errmsg("could not access directory \"%s\": %m",
fullpath)));
}
ValidatePgVersion(fullpath);
}
/* * It's now possible to do real access to the system catalogs. * * Load relcache entries for the system catalogs. This must create at * least the minimum set of "nailed-in" cache entries. */
RelationCacheInitializePhase2();
/* * Figure out our postgres user id, and see if we are a superuser. * * In standalone mode and in the autovacuum process, we use a fixed id, * otherwise we figure it out from the authenticated user name. */if (bootstrap || autovacuum)
{
InitializeSessionUserIdStandalone();
am_superuser = true;
}
elseif (!IsUnderPostmaster)
{
InitializeSessionUserIdStandalone();
am_superuser = true;
if (!ThereIsAtLeastOneRole())
ereport(WARNING,
(errcode(ERRCODE_UNDEFINED_OBJECT),
errmsg("no roles are defined in this database system"),
errhint("You should immediately run CREATE USER \"%s\" CREATEUSER;.",
username)));
}
else
{
/* normal multiuser case */
InitializeSessionUserId(username);
am_superuser = superuser();
}
/* set up ACL framework (so CheckMyDatabase can check permissions) */
initialize_acl();
/* * Read the real pg_database row for our database, check permissions and * set up database-specific GUC settings. We can't do this until all the * database-access infrastructure is up. (Also, it wants to know if the * user is a superuser, so the above stuff has to happen first.) */if (!bootstrap)
CheckMyDatabase(dbname, am_superuser);
/* * If we're trying to shut down, only superusers can connect. */if (!am_superuser &&
MyProcPort != NULL &&
MyProcPort->canAcceptConnections == CAC_WAITBACKUP)
ereport(FATAL,
(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
errmsg("must be superuser to connect during database shutdown")));
/* * Check a normal user hasn't connected to a superuser reserved slot. */if (!am_superuser &&
ReservedBackends > 0 &&
!HaveNFreeProcs(ReservedBackends))
ereport(FATAL,
(errcode(ERRCODE_TOO_MANY_CONNECTIONS),
errmsg("connection limit exceeded for non-superusers")));
/* * Initialize various default states that can't be set up until we've * selected the active user and gotten the right GUC settings. *//* set default namespace search path */
InitializeSearchPath();
/* initialize client encoding */
InitializeClientEncoding();
/* report this backend in the PgBackendStatus array */if (!bootstrap)
pgstat_bestart();
/* close the transaction we started above */if (!bootstrap)
CommitTransactionCommand();
return am_superuser;
}
/* * Backend-shutdown callback. Do cleanup that we want to be sure happens * before all the supporting modules begin to nail their doors shut via * their own callbacks. * * User-level cleanup, such as temp-relation removal and UNLISTEN, happens * via separate callbacks that execute before this one. We don't combine the * callbacks because we still want this one to happen if the user-level * cleanup fails. */staticvoid
ShutdownPostgres(int code, Datum arg)
{
/* Make sure we've killed any active transaction */
AbortOutOfAnyTransaction();
/* * User locks are not released by transaction end, so be sure to release * them explicitly. */
LockReleaseAll(USER_LOCKMETHOD, true);
}
/* * Returns true if at least one role is defined in this database cluster. */staticbool
ThereIsAtLeastOneRole(void)
{
Relation pg_authid_rel;
HeapScanDesc scan;
bool result;
pg_authid_rel = heap_open(AuthIdRelationId, AccessShareLock);
scan = heap_beginscan(pg_authid_rel, SnapshotNow, 0, NULL);
result = (heap_getnext(scan, ForwardScanDirection) != NULL);
heap_endscan(scan);
heap_close(pg_authid_rel, AccessShareLock);
return result;
}